Changing threads in a sewing machine

Abstract

A sewing machine is provided for splicing together two different threads. The machine includes a thread tree with a number of thread spools with each thread thereof being inserted through flexible plastic tubing. A movable carriage assembly locates the new thread to be spliced relative to a splicing device passageway that receives the new thread to be spliced along with the old thread. The splicing device includes a front air inlet for drawing the new thread into the passageway of the splicing device and a rear air inlet for creating air turbulence during the splicing operation. Also used in moving the new thread through the passageway is an insertion drive roller connected to a pivotal rocker. A thread clamp cover connected to the rocker cooperates with the trimmer blades to trim the old thread. A thread clamp and a thread clamp magnet cooperate to hold the old thread in a desired position during the insertion of the new thread into the splicing device. A tensioning assembly is able to adjust new thread tension based on a desired tension for the new thread.

What is claimed is: 
     
       1. An apparatus for splicing a first thread with a second thread, comprising: a thread tree having a number of spools with each having a thread and including at least a first spool having a first thread and a second spool having a second thread;   a thread clamp assembly for releasably holding at least one of the first thread and the second thread; a splicing device for splicing the first and second threads together;   a carriage assembly for locating the second thread selected from the number of threads in a desired position relative to said splicing device;   means for moving at least one of the first and second threads relative to said splicing device, said means for moving including a rocker having at least a first roller connected thereto with said rocker being pivotal among a first rocker position, a second rocker position and a neutral position; and   a thread trimming device for cutting the first thread;   wherein said thread clamp assembly, said means for moving and said thread trimming device are operatively interconnected to facilitate thread clamping, moving and trimming.   
     
     
       2. An apparatus, as claimed in claim 1, wherein: said thread tree includes a number of flexible tubes, each of said tubes receiving at least one of the threads.   
     
     
       3. An apparatus, as claimed in claim 1, wherein: said thread clamp assembly includes a first clamp member and a second clamp member with the first thread being positionable therebetween.   
     
     
       4. An apparatus, as claimed in claim 3, wherein: said first clamp member includes a thread clamp and said second clamp member includes a thread clamp magnet with a force of said clamp magnet being used to attract said thread clamp to said clamp magnet.   
     
     
       5. An apparatus, as claimed in claim 1, wherein: said thread clamp assembly includes a thread clamp connected to said rocker for desired movement therewith.   
     
     
       6. An apparatus, as claimed in claim 1, wherein: said means for moving includes an insertion roller disposed adjacent a first end of said splicing device and an advance roller positioned adjacent to a second end of said splicing device.   
     
     
       7. An apparatus, as claimed in claim 1, wherein: said thread trimming device includes a thread clamp cover and a blade with said thread clamp cover being movable to position the first thread for cutting by said blade.   
     
     
       8. An apparatus, as claimed in claim 7, wherein: said means for moving includes a rocker and said thread trimming device includes a thread clamp cover with said thread clamp cover being connected to said rocker and said thread clamp cover being movable with said rocker.   
     
     
       9. An apparatus, as claimed in claim 8, wherein: said thread clamp assembly includes a thread clamp and said thread trimming device includes a shaft that connects said thread clamp cover to said rocker with said thread clamp cover being movable with said rocker while said thread clamp remains substantially stationary. 
     
     
       10. An apparatus, as claimed in claim 1, wherein: said carriage assembly includes a pre-tensioning device. 
     
     
       11. An apparatus, as claimed in claim 1, wherein: said splicing device is a single, one-piece unit having a passageway with a number of different cross-sections.   
     
     
       12. An apparatus, as claimed in claim 11, wherein: said splicing device includes a front air inlet for use in creating a pressure differential in said splicing device passageway.   
     
     
       13. An apparatus, as claimed in claim 12, wherein: said splicing device includes a rear air inlet for supplying air used in providing a splice between the first thread and the second thread with said front and rear inlets being pneumatically isolated from each other.   
     
     
       14. An apparatus, as claimed in claim 1, further including: a tensioning assembly operatively joined to said splicing device for adjusting the tension of the second thread after splicing between the first thread and the second thread.   
     
     
       15. An apparatus, as claimed in claim 14, wherein: said tensioning assembly includes a predetermined thread tension value and means for comparing actual tension of the second thread with said predetermined thread tension value for determining whether to adjust the tension of the second thread.   
     
     
       16. An apparatus, as claimed in claim 14, wherein: said tensioning assembly includes a sensing assembly for detecting tension of the second thread, an output of said sensing assembly being compared with a stored, predetermined value associated with a desired tension of the second thread.   
     
     
       17. An apparatus for splicing a first thread with a second thread, comprising: a thread tree having a number of thread spools each having a thread and including a first spool having a first thread and a second spool having a second thread;   a thread clamp assembly for releasably holding the first thread;   a carriage assembly for locating the second thread selected from the number of threads in a desired position;   a splicing device for splicing the first and second threads together;   means for moving at least one of the first and second threads relative to said splicing device; and   a thread trimming device for cutting the first thread; wherein   wherein   said means for moving moves the second thread in both a first direction and a second opposite direction during splicing of the first and second threads and said means for moving includes an insertion drive roller and an advance drive roller with each of said drive rollers being movable using a single motor.   
     
     
       18. A method for splicing a first thread with a second thread, comprising: providing a first thread;   locating a second thread in desired positions relative to a splicing device;   trimming said first thread to provide a end;   causing said second thread to be positioned in a passageway of said splicing device; and   splicing said first and second threads together using said splicing device after said trimming step and by supplying air to said splicing device to create a turbulent air flow over said first and second threads, with both of said first and second threads moving in a first direction along lengths of said first and second threads and then moving in a second direction along length of said first and second threads during the time-said first thread and said second-thread are being spliced together.   
     
     
       19. A method, as claimed in claim 18, wherein: said locating step includes moving a carriage assembly having a number of threads to cause lateral displacement of the first thread relative to said passageway of said splicing device.   
     
     
       20. A method, as claimed in claim 19, wherein: said moving step includes causing said first thread to be positioned for trimming using a trimmer blade.   
     
     
       21. A method, as claimed in claim 18, wherein: said trimming step includes moving a rocker to a first rocker position so that the first thread is positioned for trimming.   
     
     
       22. A method, as claimed in claim 21, wherein: said-step of moving said rocker includes causing a portion of said first thread to be held in place using a thread clamp.   
     
     
       23. A method, as claimed in claim 21, wherein: said step of moving said rocker includes causing a thread clamp cover to provide cutting engagement between a trimmer blade and the first thread.   
     
     
       24. A method, as claimed in claim 18, wherein: said trimming step includes moving a rocker to a neutral position for causing a thread clamp cover to lift away from a trimmer blade and a thread clamp to hold the end of the first thread.   
     
     
       25. A method, as claimed in claim 18, wherein: said trimming step includes rotating a thread insertion roller to cause said first thread to be retracted away from a trimmer blade.   
     
     
       26. A method, as claimed in claim 18, wherein: said locating step includes moving a carriage assembly having a number of holes including a second thread hole having said second thread therein relative to said passageway of said splicing device.   
     
     
       27. A method, as claimed in claim 26, wherein: said step of moving said carriage assembly includes locating said second thread hole a distance past said splicing device passageway and then returning said second thread hole for alignment with said splicing device passageway.   
     
     
       28. A method, as claimed in claim 18, wherein: said causing step includes contacting said second thread with a thread insertion roller.   
     
     
       29. A method, as claimed in claim 18, wherein: said causing step includes creating a pressure differential in said splicing device tending to draw said second thread relative to said splicing unit.   
     
     
       30. A method, as claimed in claim 18, wherein: said causing step includes metering a distance related to movement of said second thread relative to said splicing device.   
     
     
       31. A method, as claimed in claim 18, wherein: said causing step includes moving an insertion drive roller and using air in drawing said second thread relative to said splicing device.   
     
     
       32. A method, as claimed in claim 18, wherein: said splicing step includes moving a rocker to a second rocker position for clamping said first and second threads using a thread advance drive roller.   
     
     
       33. An apparatus for splicing a first thread with a second thread, comprising: a thread tree for holding a plurality of spools of thread;   a splicing device for joining the first thread to the second thread, wherein the first thread and the second thread are each taken from a spool on said thread tree; and   means for feeding the second thread to said splicing device so that the second thread can be joined to the first thread, said means for feeding includes an insertion roller disposed adjacent a first end of said splicing device and an advance roller positioned adjacent to a second end of said splicing device.   
     
     
       34. An apparatus as claimed in claim 33, further comprising: a thread tensioner;   a take-up lever; and   a reciprocating needle;   wherein said splicing device includes a splice chamber and a splice tube for injecting compressed air into said splice chamber; and   wherein said means for feeding is located between said thread tree and said splicing device.   
     
     
       35. An apparatus, as claimed in claim 34, further comprising: a thread select carriage, located between said thread tree and said means for feeding, and having a plurality of openings wherein, each opening can guide one thread; and   a drive motor for moving said thread select carriage at right angles to an operating direction of said means for feeding so that one of said plurality of openings is in the operating path of said means for feeding.   
     
     
       36. An apparatus, as claimed in claim 35, further comprising: a thread trimming device for cutting the first thread.   
     
     
       37. An apparatus, as claimed in claim 35, wherein: said means for feeding includes means for gripping a thread projecting from said thread select carriage.   
     
     
       38. An apparatus for splicing a first thread with a second thread, comprising: a thread tree having a number of spools with each having a thread and including at least a first spool having a first thread and a second spool having a second thread;   a thread clamp assembly for holding at least one of the first thread and the second thread;   a splicing device for splicing the first and second threads together;   a carriage assembly for locating the second thread selected from the number of threads in a desired position relative to said splicing device;   means for moving at least one of the first and second threads relative to said splicing device;   a needle thread trimming device for cutting the first thread, said thread trimming device including a thread clamp cover and a blade with said thread clamp cover being movable to position the first thread for cutting by said blade; wherein said thread clamp assembly, said means for moving and said thread trimming device are operatively interconnected to facilitate thread clamping, moving and trimming, said means for moving including a rocker and said thread clamp cover being connected to said rocker and being movable therewith, said thread clamp-assembly including a thread clamp and said thread trimming device including a shaft that connects said thread clamp cover to said rocker with said thread clamp cover being movable with said rocker while said thread clamp remains substantially stationary.   
     
     
       39. A method for splicing a first thread with a second thread, comprising: providing a first thread;   locating a second thread in desired positions relative to a splicing device;   trimming said first thread to provide an end, said trimming step including rotating a thread insertion roller to cause said first thread to be retracted away from a trimmer blade;   causing said second thread to be positioned in a passageway of said splicing device; and   splicing said first and second threads together using said splicing device after said trimming step.   
     
     
       40. A method for splicing a first thread with a second thread, comprising: providing a first thread;   locating a second thread in desired positions relative to a splicing device;   trimming said first thread to provide an end;   causing said second thread to be positioned in a passageway of said splicing device, said causing step including contacting said second thread with a thread insertion roller; and   splicing said first and second threads together using said splicing device after said trimming step.   
     
     
       41. A method for splicing a first thread with a second thread, comprising: providing a first thread;   locating a second thread in desired positions relative to a splicing device;   trimming said first thread to provide an end;   causing said second thread to be positioned in a passageway of said splicing device, said causing step including moving an insertion drive roller and using air in drawing said second thread relative to said splicing device; and   splicing said first and second threads together using said splicing device after said trimming step.   
     
     
       42. A method for splicing a first thread with a second thread, comprising: providing a first thread;   locating a second thread in desired positions relative to a splicing device;   trimming said first thread to provide an end;   causing said second thread to be positioned in a passageway of said splicing device; and   splicing said first and second threads together using said splicing device after said trimming step, said splicing step including moving a rocker to one rocker position for clamping said first and second threads using a thread advance drive roller.